Bae Hyun-sung made his acting debut in 2018 with a small role in the tvN romantic comedy What’s Wrong With Secretary Kim. He then landed a recurring role in the third season of the 2018 web series Love Playlist. In 2019, he returned for its fourth season as one of its main characters. That same year, he became part of the MBC series Extraordinary You. In 2020 and 2021, he appeared in the first and second seasons of the hit tvN drama Hospital Playlist. In 2022, he played a supporting role in Our Blues, which also aired on tvN. He then starred in the MBC college romance series Dear. M. He next joined the main cast of the 2022 Olleh TV/seezn drama Gaus Electronics.